Whilst the compost is breaking down in my garden bed will it be drawing nitrogen and nutrients from my existing (luscious soil(, in order to break down?

Whilst the compost is breaking down in my garden bed will it be drawing nitrogen and nutrients from my existing (luscious soil(, in order to break down?

The good news is that the food waste that you put into your Subpod supplies plenty of nitrogen to feed the microbes that will be decomposing it.  
There is no risk of depleting the nitrogen from the surrounding soil while the compost is being produced within Subpod.